They don't. There are already tons of available topics on thsi subject - so do a search.

Fruit is just food that's generally good for you - there is no such thing as a 'fat-burning' food. Actually, fruit can be tricky because things like pineapple, mangos and whatnot can be loaded with natural sugars that your body will be more than happy to convert to fat if you don't burn them off.

I stick with apples, grapefruit and the occasional banana. I would buy kiwi's but I generally forget to buy them. Oranges can be pretty high in sugar as well, but don't hesitate to eat at least some fruits every day - just take their calories into consideration as you normally would with other foods.

I've found blueberries to be an exceptionally good fruit to eat on a diet. A few of them go a very long way. I keep a bag of frozen ones because I like to eat them straight from the bag that way. They go in my oatmeal a lot in the morning too. And in my smoothies. Last weekend my friends discovered that a few frozen blueberries are a good chaser for a nasty shot of alcohol and ate all mine up though. :-(

I also eat ridiculously huge quantities of apples. They are so self contained and tidy, easy to throw in a lunch, and they sub well for a dessert baked with cinnamon on them. We have an orchard near here and I probably go through a half bushel every month. It's an odd day that at least two apples don't go down the hatch.

Fruits don't burn fat, but they DO contain a lot of nutrients. If you eat them INSTEAD OF an unhealthy treat, then they are a fabulous deal. If you eat them IN ADDITION TO an unhealthy treat, they only make the problem worse.